IMHO Neymar is the main problem. Messi should play behind Mbappe and Poch uses Neymar there. As a consequence Messi is isolated on the right flank. I honestly think that Messi and Mbappe would play much better without Neymar. When Neymar played for Barca he was LW but now he drifts towards the middle all of the time and that creates problem for both Messi and Neymar. Currently PSG has front 3 who are constantly entering each other's space and as a consequence they are all struggling to create chances and score goals. The way I see things is that pressing and defending is secondary problem for PSG. Much bigger problem is that MNM front line isn't creating chances as everyone expected they will. They are really struggling in attack. Poch should really try to figure that out ASAP or they will get smashed in the knockout stages of CL.